The transition from adolescence to adulthood is a critical period in the life course that has important implications for subsequent achievements and behaviors. Although several studies have provided descriptive accounts of the transition to adulthood, we still know little about (1) the determinants of different life-course trajectories and (2) the consequences of following different paths to work, marriage, and parenthood. This project aims to answer these questions by prospectively investigating the transition from adolescence to adulthood in a large, unselected birth cohort of 1037 subjects in the Dunedin (New Zealand) Multidisciplinary Health and Development Study. The sample members were born in 1972-73; health, educational, psychological, social, and family data have been collected for the cohort semiannually since birth. The project proposed herein is a follow-up, designed to collect data on the transition period between adolescence and young adulthood--on educational, employment, and reproductive trajectories--and to assess the functioning of subjects in their new roles, as workers, spouses, and parents. The aims are to examine the childhood and adolescent determinants of variations in the transition to adulthood, with special emphasis on the unique challenges facing young women in their transition to adulthood, and to examine the mental-health implications of variations in the transition to young adulthood, with a focus on estimating the contribution of social-selection and socialization processes to mental health problems in this developmental period. Knowledge of linkages between early personality differences and variations in the transition to adulthood may provide information useful toward several goals: (1) Identification of persons at risk for developing mental health problems in young adulthood; (2) increased understanding of the intergenerational transmission process; and (3) testing of developmental theories about how early personality differences are related to the negotiation of important life tasks.